Field of the Invention
This invention relates to photographic apparatus. More particularly, it concerns a camera and camera lens masking accessory kit by which a normally automated single-image exposure and film transport cycle may be converted to a multiple image exposure sequence in which any one of several lens masks in the accessory kit may be used to establish a multiple image format.
The Prior Art
U.S Pat. Nos. 3,283,685; 3,443,499; 3,726,198; 4,140,381; and 4,175,843 are illustrative of prior patents disclosing cameras designed to expose each of several selected areas of a single photographic film frame to a separate light image. A feature common to all of the cameras disclosed in these patents, as well as other multiple format cameras of the prior art, is the inclusion of light blocking or confining means at the film plane of the camera to delineate very precisely the area of each one of a plurality of exposure frames. For example, in Cummins--U.S. Pat. No. 3,283,685 and Gianino--U.S. Pat. No. 3,443,499, cell-like partitions within the camera body confine image light from each of a plurality of objective lenses to a preestablished one of several image frame areas at the film plane; Bjork et al--U.S. Pat. No. 3,726,198 use a movable camera back to present adjacent image frame areas on a single film to a single exposure window; and Douglas--U.S. Pat. No. 4,140,381 and 4,175,843 employ movable opaque masks at the film plane to block light from all but the frame area to be exposed. Except for the camera shown in Douglas '381, all of the camera designs disclosed in the aforementioned patents additionally are confined to a given multiple image format and thus represent specialized photographic equipment as distinguished from general purpose cameras.
Although the camera disclosed in Douglas '381 is capable of adjustment to expose either one large image frame or as many as four separately exposed smaller image frames, the internal mechanism required for operation of focal plane masks in Douglas '381 is complex and costly. Also, the film transport system in this disclosure is manually operated. The additional requirement by the design for a turret carried shiftable objective lens and special shutter mechanism characterize this camera of the prior art as one intended primarily for successive multiple image exposures and secondarily with a capability for a single image format. As such, the design of Douglas '381 falls short of a design which may be characterized as a low cost, general purpose camera with multiple image format capability.
In addition to the prior art represented by the aforementioned U.S. patents, it is known in the photographic art that separate areas of a single film frame can be exposed to different images by masking portions of the camera objective lens. For example, one half of the objective lens may be masked to expose a corresponding one half of the single film frame. Then the other half of the lens may be masked to expose the remaining half of the same film frame. This technique is used by photographers to create special effects in photographs and in some instances to save film. Masking devices used for such techniques however are usually hand made and cumbersome to use particularly by amateur photographers. Also, such techniques are very difficult if used with cameras having a completely automated exposure cycle including automatic film advance upon the completion of each exposure cycle.